Case study of the development of polar stratospheric clouds using bistatic imaging

International audienceThe formation of polar stratospheric clouds (PSCs) is closely related to wave activity on different scales since waves propagating into the stratosphere perturb the temperature profile. We present here a case study of the development of visible PSCs (mother-of-pearl clouds), appearing at the polar vortex edge on 9 January 1997, under-taken by means of ground-based cameras. It is shown that the presence of stratospheric clouds may be detected semi-automatically and that short-term dynamics such as altitude variations can be tracked in three dimensions. The PSC field showed distinct features separated by approximately 20 km, which implies wave-induced temperature variations on that scale. The wave-induced characteristics were further emphasised by the fact that the PSCs moved within a sloping spatial surface. The appearance of visible mother-of-pearl clouds seems to be related to leewave-induced cooling of air masses, where the synoptic temperature has been close to (but not necessarily below) the threshold temperatures for PSC condensation

Characterization of polycyclic aromatic compounds in historically contaminated soil by targeted and non-targeted chemical analysis combined with in vitro bioassay

Soil samples from a contaminated site in Sweden were analyzed to identify the presence of 78 polycyclic aromatic compounds (PACs) using gas chromatography coupled with mass spectrometry (GC-MS). The target analysis revealed large contributions not only from polycyclic aromatic hydrocarbons (PAHs), but also from alkylated- and oxygenated-PAHs (alkyl- and oxy-PAHs, respectively), and N-heterocyclics (NPACs). PAC profiles indicated primarily pyrogenic sources, although contribution of petrogenic sources was also observed in one sample as indicated by a high ratio of alkylated naphthalene compared to naphthalene. The aryl hydrocarbon receptor (AhR)-activity of the soil extracts was assessed using the H4IIe-pGudluc 1.1 cells bioassay. When compared with the calculated total AhR-activity of the PACs in the target list, 35-97% of the observed bioassay activity could be explained by 62 PACs with relative potency factors (REPs). The samples were further screened using GC coupled with OrbitrapTM high resolution MS (GC-HRMS) to investigate the presence of other PACs that could potentially contribute to the AhR-activity of the extracts. 114 unique candidate compounds were tentatively identified and divided into four groups based on their AhR-activity and environmental occurrence. Twelve substances satisfied all the criteria, and these compounds are suggested to be included in regular screening in future studies, although their identities were not confirmed by standards in this study. High unexplained bio-TEQ fractions in three of the samples may be explained by tentatively identified compounds (n = 35) with high potential of being toxic. This study demonstrates the benefit of combining targeted and non-targeted chemical analysis with bioassay analysis to assess the diversity and effects of PACs at contaminated sites. The applied prioritization strategy revealed a number of tentatively identified compounds, which likely contributed to the overall bioactivity of the soil extracts

Comparison between manual scaling and Autoscala automatic scaling applied to Sodankylä Geophysical Observatory ionograms

This paper presents a comparison between standard ionospheric parameters manually and automatically scaled from ionograms recorded at the high-latitude Sodankylä Geophysical Observatory (SGO, ionosonde SO166, 64.1° geomagnetic latitude), located in the vicinity of the auroral oval. The study is based on 2610 ionograms recorded during the period June–December 2013. The automatic scaling was made by means of the Autoscala software. A few typical examples are shown to outline the method, and statistics are presented regarding the differences between manually and automatically scaled values of F2, F1, E and sporadic E (Es) layer parameters. We draw the conclusions that: 1. The F2 parameters scaled by Autoscala, foF2 and M(3000)F2, are reliable. 2. F1 is identified by Autoscala in significantly fewer cases (about 50 %) than in the manual routine, but if identified the values of foF1 are reliable. 3. Autoscala frequently (30% of the cases) detects an E layer when the manual scaling process does not. When identified by both methods, the Autoscala E-layer parameters are close to those manually scaled, foE agreeing to within 0.4 MHz. 4. Es and parameters of Es identified by Autoscala are in many cases different from those of the manual scaling. Scaling of Es at auroral latitudes is often a difficult task

Broadband Meter-Wavelength Observations of Ionospheric Scintillation

Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array (LOFAR) technology at the Kilpisj\"arvi Atmospheric Imaging Receiver Array (KAIRA) station in northern Finland we have observed scintillations over a 3 octave bandwidth. ``Parabolic arcs'', which were discovered in interstellar scintillations of pulsars, can provide precise estimates of the distance and velocity of the scattering plasma. Here we report the first observations of such arcs in the ionosphere and the first broad-band observations of arcs anywhere, raising hopes that study of the phenomenon may similarly improve the analysis of ionospheric scintillations. These observations were made of the strong natural radio source Cygnus-A and covered the entire 30-250\,MHz band of KAIRA. Well-defined parabolic arcs were seen early in the observations, before transit, and disappeared after transit although scintillations continued to be obvious during the entire observation. We show that this can be attributed to the structure of Cygnus-A. Initial results from modeling these scintillation arcs are consistent with simultaneous ionospheric soundings taken with other instruments, and indicate that scattering is most likely to be associated more with the topside ionosphere than the F-region peak altitude. Further modeling and possible extension to interferometric observations, using international LOFAR stations, are discussed.Comment: 11 pages, 17 figure

Treatment in the context of confinement: – understanding the barriers and possibilities for facilitating change in at-risk youth

AbstractIn this article the authors present a meta-synthesis of their studies on secure institutions in Sweden and Denmark. The aim of the metasynthesis is to explore how the context of confinement shapes the possibilities for providing treatment and positive change for at-risk youth. Drawing on meta-synthesis methodology the authors extract content from nine studies published in 20 articles. We highlight three dimensions, which are a) treatment practices and behavioural regulation, b) the carceral materialities and sociomaterial practices, and c) relations. We argue that while treatment is curtailed by confinement, improvements can be made to support more successful change among at-risk youth and smooth their transition into adulthood. Artiklen præsenterer en metasyntese af ni studier om sikrede institutioner i Danmark og Sverige. Formålet med metasyntesen er at undersøge, hvordan frihedsberøvelse rammesætter behandling og forandringsarbejde med unge i udsatte positioner. Forfatterne analyserer 20 artikler fordelt på ni studier, de selv har gennemført. Analysen har fokus på tre centrale forhold; a) behandlingsarbejde og adfærdsregulering, b) materialitet og sociomaterielle praktikker, og c) relationer. Vi argumenterer for, at behandling påvirkes af frihedsberøvelse, men med forbedringer kan behandling på sikret institution bidrage til at skabe positiv forandring og sikre de unges overgang til voksenliv

Parameterisation of the chemical effects of sprites in the middle atmosphere

Transient luminous events, such as red sprites, occur in the middle atmosphere in the electric field above thunderstorms. We here address the question whether these processes may be a significant source of odd nitrogen and affect ozone or other important trace species. A well-established coupled ion-neutral chemical model has been extended for this purpose and applied together with estimated rates of ionisation, excitation and dissociation based on spectroscopic ratios from ISUAL on FORMOSAT-2. This approach is used to estimate the NO<sub>x</sub> and ozone changes for two type cases. <br><br> The NO<sub>x</sub> enhancements are at most one order of magnitude in the streamers, which means a production of at most 10 mol per event, or (given a global rate of occurrence of three events per minute) some 150–1500 kg per day. The present study therefore indicates that sprites are insignificant as a global source of NO<sub>x</sub>. Local effects on ozone are also negligible, but the local enhancement of NO<sub>x</sub> may be significant, up to 5 times the minimum background at 70 km in extraordinary cases

Mental health, welfare or justice: An introductory global overview of differences between countries in the scale and approach to secure placements of children and young people.

BACKGROUND: Estimates suggest that over a million children per year are deprived of their liberty across the world. Little is known about the types, ethos or distribution of secure beds in which they are detained. AIM: This study aims to provide quantitative data with background information, to explore similarities and differences across jurisdictions, and to inform critical inquiry into key concepts and practices. METHODS: Data was obtained using an opportunistic sample of affluent countries, derived from an emerging academic/practice network of senior professionals. Depending on jurisdiction, data was already in the public domain or specifically requested. Data requests were related to the nature and size of health, welfare and criminal justice elements of secure beds and recent occupancy. Key professionals working in child secure settings, within jurisdictions, provided commentary on local approaches. RESULTS: Data was incomplete but allowed for comparisons between 10 jurisdictions. The proportions of the populations of children and young people detained varied by jurisdiction as did their distribution across variations of secure settings. Not all jurisdictions had all three kinds of secure settings. Definitions of secure beds varied depending on the use of relational, procedural or physical security. CONCLUSION: Findings are tentative but suggestion solely considering numerical descriptions of children's detention is misleading; our study highlights ways in which comparative studies may be improved. Within reported jurisdictions, the framework of health, welfare and justice was meaningful but this may not hold true with a wider international application of this method. Open interrogation of this data would be enhanced by the inclusion of children's perspectives